About John

John Lipscomb is a senior toxicologist for CTEH®, LLC. His scientific career began in 1984 at the bench as a Principal Investigator at the National Center for Toxicological Research (U.S. FDA, Jefferson, AR). There, he completed research requirements for his Master’s and Doctorate degrees by performing experiments to characterize the adult and transplacental pharmacokinetics of trimethyltin, a potent neurotoxicant. Later his studies expanded to include mechanistic and enzyme inhibition. In 1991, Dr. Lipscomb began active duty service in the U.S. Air Force, posted at Wright-Patterson AFB in Dayton, Ohio. Dr. Lipscomb supported investigations into the pharmacokinetics of mission-critical compounds, like trichloroethylene and halon replacement chemicals. His work pioneering the military’s first large-scale investigation of human metabolic variability earned him the Air Force Achievement medal. During his time at the Air Force, his Metabolism Section produced 15 peer-reviewed government technical reports. Following completion of active duty in 1998, he accepted a position in the EPA’s National Center for Environmental Assessment in Cincinnati, in the Division in which EPA’s Integrated Risk Information System (IRIS) originated and was maintained until 2000.

While at the EPA, Dr. Lipscomb initially undertook toxicology and dose-response responsibilities on a project aimed at quantifying the negative health impact of drinking water disinfection byproducts in comparison to the positive health impact of avoiding microbially-induced disease. He was invited to join the the Division’s work in chemical mixtures, where he was the sole toxicologist contributing to EPA’s guidances on chemical mixtures and cumulative risk. These guidances were developed specifically for application at Superfund sites. Dr. Lipscomb also served as Chemical Manager for several IRIS assessments, and developed several Provisional Peer-Reviewed Toxicity Value (PPRTV) assessments specifically requested by the EPA’s Office of Land and Emergency Response. Following an internal transfer to the EPA’s National Homeland Security Research Center (NHSRC), Dr. Lipscomb assumed overall responsibility for its Provisional Advisory Levels (PALs) program, initiated in 2004. Dr. Lipscomb was responsible for the development of acute and short-term exposure guidance values for oral and inhalation exposures to hazardous substances and chemical warfare agents. He developed and lectured in several continuing education courses taught locally, regionally, nationally and internationally on topics of toxicology and health risk assessment. During his time at the EPA, Dr. Lipscomb authored or co-authored 25 peer-reviewed government technical reports.

Dr. Lipscomb holds certification in general toxicology as a Diplomate of the American Board of Toxicology. His contributions to the field of toxicology led to his recognition as a Fellow of the Academy of Toxicological Sciences in 2008. Dr. Lipscomb serves on the Health Advisory Board for NSF International, an organization which certifies devices, appliances, and equipment-contacting drinking water. He also serves on AIHA’s Emergency Response Planning Committee. He is a past president of the Ohio chapter of the Society for Risk Analysis and the Society of Toxicology, has served on Council for the Society of Toxicology, and is a past president of the American Board of Toxicology. He is on the editorial board and is a former Associate Editor for Toxicological Sciences and is an Associate Editor for Toxicology Mechanisms and Methods and Toxicology Reports. Dr. Lipscomb maintains an Adjuct Professorship in the Department of Pharmacology and Toxicology at the University of Louisville, where he is course director for a graduate level course, Introduction to Health Risk Assessment.

Past or Current Professional Affiliations

  • Society of Toxicology – Full Member
  • Society of Toxicology – Risk Assessment Specialty Section
  • Society of Toxicology – Mixtures Specialty Section
  • Society for Risk Analysis
  • Society for Risk Analysis – Dose Response Specialty Group
  • Society for Risk Analysis – Security and Defense Specialty Group
  • American Industrial Hygiene Association
  • American Industrial Hygiene Association – Emergency Response Planning Committee

Registrations & Certifications

  • Diplomate, American Board of Toxicology (DABT)
  • Fellow, Academy of Toxicological Sciences

Publications

  • A perspective on in vitro developmental neurotoxicity test assay results: An expert panel review, 2023
  • Evaluating risk, exposure and detection capabilities for priority chemical threats in water, 2022
  • Grouping of PFAS for human health risk assessment: Findings from an independent panel of experts, 2022
  • Toxicity data as the basis for acute and short-term emergency exposure guidance, 2021
  • See All Publications
    • A perspective on in vitro developmental neurotoxicity test assay results: An expert panel review, 2023
    • Evaluating risk, exposure and detection capabilities for priority chemical threats in water, 2022
    • Grouping of PFAS for human health risk assessment: Findings from an independent panel of experts, 2022
    • Toxicity data as the basis for acute and short-term emergency exposure guidance, 2021
    • Comparison of in vivo derived and scaled in vitro metabolic rate constants for several volatile organic compounds (VOCs), 2020
    • Purpose driven risk assessment, 2019
    • The Impact of Scaling Factor Variability on Risk-Relevant Pharmacokinetic Outcomes in Children: A Case Study Using Bromodichloromethane (BDCM), 2019
    • Application of quantitative dose response data in risk assessment and the incorporation of high throughput data, pp 559-572, 2018
    • FutureTox III: Bridges for Translation, 2017
    • The impact of variation in scaling factors on the estimation of internal dose metrics: a case study using bromodichloromethane (BDCM), 2016
    • Gaining acceptance for the use of in vitro toxicity assays and QIVIVE in regulatory risk assessment, 2015
    • Correlating In Vitro Data to In Vivo Findings for Risk Assessment, 2014
    • Assessment Report: Key Findings and Scientific Issues in the Human Health Effects of Trichloroethylene, 2013
    • Multiple Chemical Exposures and Risk Assessment, 2013
    • Case study illustrating the WHO IPCS guidance on characterization and application of physiologically based pharmacokinetic models in risk assessment, 2013
    • Application of an Updated Physiologically-Based Pharmacokinetic Model for Chloroform to Evaluate CYP2E1-Mediated Renal Toxicity in Rats and Mice, 2013
    • Putative mechanisms of Environmental Chemical-Induced Steatosis, 2012
    • Physiologically Based Pharmacokinetic (PBPK) Models in Toxicity Testing and Risk Assessment, 2012
    • Identification of developmentally toxic drinking water disinfection byproducts and evaluation of data relevant to mode of action, 2011
    • Cumulative Environmental Risk, 2011
    • Differences Between Human and Rat Intestinal and Hepatic Bisphenol-A Glucuronidation and the Influence of Alamethicin on In vitro Kinetic Measurements, 2010
    • Chemical Mixtures and Cumulative Risk Assessment, 253-281, 2010
    • PBPK Modeling, 2010
    • Co variation of human microsomal protein per gram of liver with age: Absence of influence of operator and sample storage may justify inter laboratory data pooling, 2008
    • Guidelines for the Derivation of Biomonitoring Equivalents: Report from the Biomonitoring Equivalents Expert Workshop, 2008
    • Guidelines for the Communication of Biomonitoring Equivalents: Report from the Biomonitoring Equivalents Expert Workshop, 2008
    • In Vitro Measurements of Metabolism for Application in Pharmacokinetic Modeling, 2008
    • Haloacetonitriles: Metabolism and Toxicity, 2008
    • Toxicokinetics for Drinking Water Risk Assessment, 2008
    • Approaches for Applications of Physiologically Based Pharmacokinetic Models in Risk Assessment, 2008
    • Scaling factors for the extrapolation of in vivo metabolic drug clearance from in vitro data: Reaching a consensus on values of human microsomal protein and hepatocellularity per gram of liver, 2007
    • High-to-low dose extrapolation: issues and approaches, 2007
    • Evaluation of Physiologically Based Pharmacokinetic Models for Use in Risk Assessment, 2007
    • Pharmacokinetic and Physiologically Based Pharmacokinetic Models in IRIS assessments. In: Lipscomb JC and Ohanian EV (eds), Toxicokinetics and Risk Assessment, 2007
    • Mode of Action as a Determining Factor in Human Health Risk Assessment of Chemical Mixtures, 2007
    • The Toxicity and Risk of Chemical Mixtures, 2007
    • Age-Dependent Partition Coefficients for a Mixture of Volatile Organic Solvents in Sprague-Dawley Rats and Humans, 2007
    • In Vitro Metabolism of the Fungicide and Environmental Contaminant Trans-Bromuconazole and Implications for Risk Assessment, 2007
    • Considerations of Design and Data when Developing Physiologically-Based Pharmacokinetic Models In: Lipscomb JC and Ohanian EV (eds), Toxicokinetics and Risk Assessment, 2007
    • Predicting Age-Dependent Pharmacokinetics of Six Volatile Organic Compounds in the Rat Utilizing Physiologically-Based Pharmacokinetic Modeling, 2007
    • Efecto Del Ácido Dicloroacético Sobre La Toxicidad Del Cobre Y El Arsénico En Embriones De Anfibio (Effect Of Dicloroacétic Acid On The Toxicity Of Copper And Arsenic In Amphibian Embryos), 2006
    • Issues in the Pharmacokinetics of Trichloroethylene and Its Metabolites, 2006
    • Amphitox: Un Método Rápido Para Detectar La Toxicidad Remanente Al Proceso De Desinfección Del Agua De Red. (Amphitox: A Fast Method To Detect The Toxicity Of Disinfection Byproducts In Distributed Drinking Water), 2006
    • Quantitative structure-property relationships for interspecies extrapolation of the inhalation pharmacokinetics of organic chemicals, 2005
    • Data for Physiologically-Based Pharmacokinetic Modeling in Neonatal Animals: Physiological Parameters in Mice and Sprague-Dawley Rats, 2005
    • A Feasibility Study of Cumulative Risk Assessment Methods for Drinking Water Disinfection By-Product Mixtures, 2004
    • Incorporation of Pharmacokinetic and Pharmacodynamic Data into Risk Assessments, 2004
    • The Metabolic Rate Constants and Specific Activity of Human and Rat Cytochrome P450 2E1 Toward Chloroform, 2004
    • Evaluating the Relationship between Variance in Enzyme Expression and Toxicant Concentration in Health Risk Assessment Human, 2004
    • Application of QSTRs in the Selection of a Surrogate Toxicity Value for a Chemical of Concern, 2003
    • Application of in Vitro Biotransformation Data and Pharmacokinetic Modeling to Risk Assessment, 2003
    • How Differences in Enzyme Expression Can Translate into Pharmacokinetic Variance and Susceptibility to Risk, 2003
    • Variance of Microsomal Protein and Cytochrome P450 2E1 and 3A Forms in Adult Human Liver, 2003
    • The Impact of Cytochrome P450 2E1-dependent Metabolic Variance on a Risk Relevant Pharmacokinetic Outcome in Humans, 2003
    • Health Advisory Values for Drinking Water Contaminants and the Methodology for Determining Acute Exposure Values, 2002
    • Cold and Cryopreservation of Monkey Liver Slices, 2002
    • Incorporating Human Interindividual Biotransformation Variance in Health Risk Assessment, 2002
    • Physiologically Based Pharmacokinetic Modeling of the Lactational Transfer of Methylmercury, 2001
    • Risk Assessment of Complex Mixtures of Disinfection Byproducts (DBPs): Methods for Considering Unidentified DBPs, 2001
    • U.S. EPA’s Comparative Risk Assessment, 2001
    • Metabolism of Trichloroethylene, 2000
    • Physiologically Based Pharmacokinetic Modeling of the Lactational Transfer of Methylmercury, 2000
    • Potential Health Effects of Drinking Water Disinfection Byproducts Using Quantitative Structure Toxicity Relationship, 2000
    • A Comparative Risk Assessment Methodology to Assess Drinking Water Treatment Technologies, 2000
    • Interindividual Variance of Cytochrome P450 Forms in Human Hepatic Microsomes: Correlation of Individual Forms with Xenobiotic Metabolism and Implications in Risk Assessment, 2000
    • A Multiple-Purpose Design Approach to the Evaluation of Risks from Complex Mixtures of Disinfection By Products (DBPs), 2000
    • Extrapolation Issues in Human Health Risk Assessment: Methods for Potential Use in Sex-Specific Health Evaluations, 2000
    • Identifying Potential Human Health Risks of Combustion Byproducts from Aerospace Advanced Composite Materials., 1999
    • Human Hepatocytes, A Novel Animal Alternative, 1999
    • Glutathione Conjugation of Trichloroethylene in Human Liver and Kidney: Kinetics and Individual Variation, 1999
    • Covalent Binding of Trichloroethylene to Proteins in Human and Rat Hepatocytes, 1998
    • Effect of Organ Procurement Conditions on Cytochrome P-450 Activity in Rat Liver Microsomes, 1998
    • In Vitro to in Vivo Extrapolation for Trichloroethylene Metabolism in Humans, 1998
    • Metabolism of Trichloroethylene and Chloral Hydrate by the Japanese Medaka in vitro, 1998
    • Use of Kinetic and Mechanistic Data in Species Extrapolation of Bioactivation: Cytochrome P-450 Dependent Trichloroethylene Metabolism at Occupationally Relevant Concentrations, 1998
    • Chloral Hydrate Formation in the Japanese Medaka Minnow, 1997
    • Cytochrome P450-dependent Metabolism of Trichloroethylene: Interindividual Differences in Humans, 1997
    • Combustion Products from Advanced Composite Materials, 1997
    • Role of Mouse Intestinal Microflora in Dichloroacetic Acid Formation, an in vivo Study., 1997
    • Evaluating Human Variability in Chemical Risk Assessment: Hazard Identification and Dose-Response Assessment for Noncancer Oral Toxicity of Trichloroethylene, 1996
    • Supporting Documentation for the Exposure Guidance Levels for Hydrofluorocarbon-123., 1996
    • A Species Comparison of Chloral Hydrate Metabolism in Blood and Liver. Biochem Biophys Res Commun 227(2):340-350., 1996
    • Formation of Dichloroacetic Acid by Rat and Mouse Gut Microflora, 1996
    • Mechanistic Insights Aid the Search for CFC Substitutes: Risk Assessment of HCFC-123 as an Example, 1994
    • Age and Dietary Factors in Hippocampal Sensitivity to Trimethyltin, 1992
    • Effects of Aging and Caloric Restriction on Hepatic Drug Metabolizing Enzymes in the Fischer 344 Rat. II: Effects on Conjugating Enzymes, 1989
    • The Disposition of 14C-Trimethyltin in the Pregnant Rat and Fetus, 1989
    • Fetomaternal Kinetics of Trimethyltin, 1986
    • Time-Course Alterations in the Tremor and Muscarinic Receptor Binding Produced by Trimethyltin, 1985